The study of classroom processes that shape students’ motivational beliefs, although fruitful, has suffered from a lack of conceptual clarity in terminology, definitions, distinctions, and roles of these important processes. Synthesizing extant research and major theoretical perspectives on achievement motivation, I propose Motivational Climate Theory as a guide for future research efforts toward more accurate, systematic understanding of classroom motivational processes. As an initial organizing framework, three broad categories of classroom motivational processes are defined: motivational supports, consisting of speech, actions, and structures in a setting that are controllable by the people in that setting; motivational climate, defined as students’ shared perceptions of the motivational qualities of their classroom; and motivational microclimates, or students’ individual perceptions that differ from shared perceptions. Motivational support and climate’s key characteristics and mechanisms are described, followed by recommendations, future directions, and implications for research, practice, and policy.